[Ffmpeg-devel] qprd plus bframes = low quality

[Corey Hickey]

Trent Piepho wrote:
> Using qprd with b-frames seems to give much lower quality than either b-frames
> or qprd alone.
> 
> You can see sample pictures and command line here:
> http://www.speakeasy.org/~xyzzy/qprd_b.html
> 
> vcodec=mpeg4:vbitrate=6950:dia=-4:predia=8:precmp=2:subcmp=2:cmp=2:v4mv:qpel:lmin=1:vpass=1:vqmin=2:mbd=2:trell:cbp:mv0:dc=8:sc_factor=4
> 
> with vmax_b_frames=2 and/or qprd added.

Unless Michael steps in and sees immediately what is wrong, I suggest 
that you try to (a) try to simplify your lavcopts, (b) provide a sample 
source video, and (c) provide the full command line. At the very least, 
post the full output of mencoder.

I tested qprd with two b-frames a while ago and didn't run into any 
problems. There are several possible reasons for that, but in most cases 
you need to make absolutely sure your audience can reproduce the problem 
(or see what you did wrong, which has been the case for me on more than 
one occasion).

-Corey